The new iPhone 4 natively supports basic sync with Outlook contacts and calendar direct via USB using iTunes. CompanionLink lets you sync contacts and calendar from Outlook, Lotus Notes, ACT!, Palm Desktop and others to any Google account. The iPhone 4 can then automatically sync with Google using its wireless data connection. This means you can update your calendar from your iPhone, and it will wirelessly sync back to Google and then down to your PC.
For more info, visit www.companionlink.com/iphone